Quote from: DaveJes1979 on 12/03/2018 06:40 pm5 pages of people trying to re-invent the wheel. As many in the past have pointed out - rotate a pressurized habitat linked to an empty upper stage via a few hundred feet of tethering. Quite large radii of rotation are possible with tethers.Yes I agree. For those who want to have a backup habitat module in case there is a problem, just have two side by side with an airlock between them on the same side of the spin arm and extend the cable with the counter weight a little further out and/or adjust the centre of spin on the cable.For concerns about people, liquids and things moving about and disturbing the rotational balance, I would have thought that many such movements would cancel themselves out eventually and that the residual imbalances could be dealt with by an automated system monitoring the rotational forces in 3 dimensions and adjusting counter weights inside or outside of the craft and or increasing / decreasing the rate of spin.
5 pages of people trying to re-invent the wheel. As many in the past have pointed out - rotate a pressurized habitat linked to an empty upper stage via a few hundred feet of tethering. Quite large radii of rotation are possible with tethers.
Yes I agree. For those who want to have a backup habitat module in case there is a problem, just have two side by side with an airlock between them on the same side of the spin arm and extend the cable with the counter weight a little further out and/or adjust the centre of spin on the cable.
For concerns about people, liquids and things moving about and disturbing the rotational balance, I would have thought that many such movements would cancel themselves out eventually and that the residual imbalances could be dealt with by an automated system monitoring the rotational forces in 3 dimensions and adjusting counter weights inside or outside of the craft and or increasing / decreasing the rate of spin.
Quote from: Slarty1080 on 12/06/2018 04:37 pmYes I agree. For those who want to have a backup habitat module in case there is a problem, just have two side by side with an airlock between them on the same side of the spin arm and extend the cable with the counter weight a little further out and/or adjust the centre of spin on the cable.The Dragon or Starliner capsule that brought you to the habitat is the backup. Just like with ISS, you get into it and return to earth in the event of an emergency. There will have to be a specialized docking adapter and structural provisions to connect the capsule to the habitat.QuoteFor concerns about people, liquids and things moving about and disturbing the rotational balance, I would have thought that many such movements would cancel themselves out eventually and that the residual imbalances could be dealt with by an automated system monitoring the rotational forces in 3 dimensions and adjusting counter weights inside or outside of the craft and or increasing / decreasing the rate of spin.You already have to have an RCS to spin up the stack in the first place. No need to add more mass and complexity.
But why is that necessary for such a small habitat, with a trained crew?
Quote from: Paul451 on 12/11/2018 07:40 amBut why is that necessary for such a small habitat, with a trained crew?Tethers are light.
Also, who says you will have a trained crew (rather than untrained passengers on the way to Mars)?
But unstable and historically error-prone.
(The best "tether" option seems to be to combine it with a pressurised tube to put the tethers/cables under tension, tethers to put the pressure-tube under compression. Increases the vibrational and twisting stability over either alone.)
The topic of the thread, DSH.